Well I leveled my JC on my DK tonight from 1-430 (~3500-4000g) and made myself a ruby hare, monarch crab, and made one solid dragon's eye. Wow. Between those 3 things My tank's HP went from 24.6k to 27.3k, almost a 3k hp gain. Plus my dodge went up by almost 1% and my defense went up by 3 points. Totally worth it, AND I can still make 2 more JC gems, probably 1 more solid dragon's eye and 1 +27 dodge gem, can't wait! Overgearing the tank just makes instances that much easier. Now I need to get some extra hp on my shamans for aoe protection.